Electric foot-switch.



G. A. LUNDGREN. ELECTRIC FOOT SWITCH.

APPLICATION FILED $EP'1". 19, 1910. 1,031,191. Patented Ju1y2, 1912.

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ill!" u UNITED STATES PATENT OFFICE.

CHARLES AUGUST LUND GREN,

01? DETROIT, MICHIGAN, ASSIGNOR TO BURROUGHS ADDING MACHINE COMPANY, o'E DETROIT, MICHIGAN, A CORPORATION or MICHIGAN.

ELECTRIC FOOT-SWITCH.

Specification of Letters Patent.

Patented July 2,1912.

Application filed September 19, 1910. Serial No. 582,676.

To all whom it may concern.

Be it known that l, CHARLES .li or s'r liunoorncx, a citizen of the United States, re-

siding at Detroit, in the county of Vl ayne .and immunity from derangement or deterioration in use. p

It will be understood that the general'purpose of such a device as that upon which I seek to improve is to not only effectively close the circuit upon depression of a foot piece or treadle but. to maintain full contact of electrodes notwithstanding there may be slight relaxation of foot pressure, while at the same time the switch will open upon re lease of the'foot-piece or treadle.

In the drawings'which accompany and form part of this specification, Figure 1 represents the switch of my invention .in perspective andin an open condition; Fig. 2 is a side elevation of a-portion of the construction illustrating a changed relation as compared with Fig. 1, to wit, that which obtains when the switch is closed; Fig. 3 is a cross section on the line 3-3 of Fig. 1 and including an inclosing casing.

The reference numeral 3 designates a baseboard of insulating material which is mounted upon and secured to metal base block or plate 3 and the reference numeral a designates upright end plates secured to the baseboard or plate and one having a bushing 5 through which a cableb is introduced con-' taining wiring, and the other having an opening 7 extending upward a considerabledistance to accommodate the foot lever 8. The latter is pivotedin a bifurcated block 9 secured to the baseboard 2 and base plate 3 and curves downward extending through' a cut back portion 9 ofthe baseboard 2 and av similar cutback portion of the base plate 3 and thence out- I through yond projects latter, said stud. 26 normally being in the studs 16 and 2G crank latch the opening '7 be-' whichit takes the form of a foot switcher treadle 10, An GXPfiIlSlOIl' spring 11 is interposed between the baseboard and sald lever on the forward side of the latters pivot thus tending to elevate the footswitch or treadleu There is pivoted to an.- other bifurcated block or post 12 a switch lever composed of a body portion 13 of insulating material and metal blades 14, said '12 being secured to "the base plate by a screw 1. L, Fig. 3, entered through said plate and the insulatingbaseboard 2. The said switch lever is normally drawn downward as to its forward end by a contractile spring 15 and has a stud 1 6 projecting from one side over a laterally-bent or offset portion of the rear arni 8 of the lever 8. Obviously depression of the treadle 10 rocks the lever 13 lowering its blades 1st; The latter are adapted to enter contact clips 16 secured to conductor blocks 17 mounted on the base plate 2 and having binding posts 18 to which the wires of the cable 6 are attached.

Such rocking of said lever 8 is limited by its contact with a stud or post 19 rising from the baseboard. Thelever 8 is limited as to normal position by contact of a lateral stud 20 with one side of the'post 9 There is mounted upon the and secured .to it and the base plate 3 a third bifurcated post or block 21 in which is-pivote d a latch 22 of bell crank form. The upstanding portion of said latch has a catch-shoulder 23 upwardly beyond a beveled edge 24 and there is a guard portion 25 projecting beyond said catch shoulder. The

stud 26 projects over the switch lever on the side opposite that from which the stud 16 and may in fact -.be integral with the plane below thecatch shoulder 2 The will preferably carry rollers for anti-friction purposes. An expansion spring 30 between the baseboard 2 and the forwardly extending branch of the bell 22 tends to elevate said branch and swing the other branch rearward, but is. normally restrained by reason of engagement between the rear arm 8 of the foot lever 8 and a stud 31 projecting laterallv from said forward branch of the bell cranh latch, the stud being preferably rollerequipped. Upon depression of the treadle 10-pressure on said stud 31 is relieved so that the bell crank" latch may rock under action ofits spring 30 and the beveled edge 24; be

baseboard carried into the'path ot the stud 26 on the switch lever which lever is of course rocking at the same time. The continued rocking ot said lever causes said stud to act against the inclined edge A and slightly displace the latch against the stress of its spring 30, until the stud passes the shoulder 23 whereupon the. spring 30 expands and causes the shoulder 2 to spring under and cam the said stud upwardly. as illustrated in Fig. 2. Thus the switch lever is given impetus at this period and closes with a snap, the contact plates l4 striking against the limit post 1 as they engage the terminal clips 16. The lever 'is of course locked down by the shoulder Q -Junder the stud 26. This extreme depression of the treadle carries its rear arm slightly above the stud 31 and as :in addition to this some degree of movement of the catchis necessary before its shoulder becomes disengaged from the stud 26, it is obvious that a certain amount of play of the tooblever is permissible without the switch being unlocked. At the same time release of the treadle or foot lever will result-in the unlocking of the switch lever and its springing to open position.

It will be understood that the foot lever spring 11 is superior in strength to the latch spring 30, and furtl'ier, that the springing of switch lever to the open position produces a snap or report as the stud 16 lands against the rear arm of the treadle with considerable force. The switch lever spring 15 is anchored at its lower end to a clip -l-0 held a ainst the baseboard by the post 21.

It will be noted that the above described construction provides for a sort of alarm in the term of a snap, occurring as an incident to the closing and opening otthe switch. This serves to signify and emphasize the open or closed condition of switch to the operator. It further provides for closing and opening of the switch by a comparatively lin'iited movement of the treadle and consequent J the latter can occupy "aposition quite close to the floor on whica the switch device rests. This contributes to the comfort of the user in that his foot does not have to be held at a sharp angle or moved to any considerable extent in'worle ing the switch. It is obvious that the object primarily stated is well fulfilled by the construction shown and described.

The parts are inclosed in a casing 50 which fits over the end plates 4; and against the side edges of the baseboard 2 and metal base plate 3 and is secured to'the latter. It will'be seen that the construction will thus be well protected "from dust and dirt.

Having now described a manner of carrying out-my invention, what I claim is:

1. In a foot. switch, a suitable supporting base, a switch lever pivoted intermediate its ends on the base, a spring normally holding the switch lever open, a catch arranged to engage the rear end of the switch lever and hold it elevated, a foot lever adapted and arranged to engage the switch lever to close the switch when the treadle is depressed and to engage the catch to release the switch lever when the treadle is released.

2. In' a foot switch, the combination of a suitable supporting base, a foot lever pivoted thereto intermediate its ends and having a treadle at one end, a switch lever pivoted to the base intermediate its ends and having a portion overlying the inner arm of the foot lever and also having a catch stud, and a latch 0t bell crank form pivoted to the base and having on one branch a shoulderto' engage said catch stud and on the other branch a portion extending under the footlever; the latter, the switch lever,

and the latch being spring-actuated.

3. In a foot switch, the combination of a suitable supporting base, a foot lever pivoted thereto intermediate its ends and having a projecting treadle portion, a switch lever pivoted to the base and having a projecting stud extending over the inner arm of said foot lever and also having a catch stud, and a latch of bell crank form having a shoulder on one branch to engage said catch stud and a stud on the other branch extending under the inner arm of the foot lever; the latter, the switch lever and the latch being spring-actuated.

CHARLES AUGUST LUNDGREN.

lVitnesses J. G. VINCENT, ARTHUR N. FRENZEL. 

